This invention relates to a method for providing a sterile inert atmosphere in an aseptic packaging machine wherein an inert gas is passed through a microbiological filter and then sparged through a bath of hot sterilizing liquid into the interior of the machine. A portion of the sterile inert gas is withdrawn from the machine interior by means of a suitable pump or blower, and separated into three parts; the first part being passed through a heater and then over the flange sealing areas of containers passing through the machine to dry same prior to heat sealing operations, the second part being directed to the machine filler means to provide a back-up microbiological barrier for the filler, and the third part being passed through jets aligned on either side of the web of cover material as the cover material emerges from a sterilant bath, said jets being arranged to blow off liquid sterilant adhering to the cover web.
By definition, aseptic packaging is a packaging method whereby presterilized food product is filled into presterilized containers or cups under sterile conditions, the cups then sealed under sterile conditions, and the sealed cups delivered into commerce without further sterilization treatment. In other words, sterile food product, sterile containers and sterile covers are brought together in an atmosphere of sterile inert gas, combined into a package of a food product which requires no further sterilization, and one which does not require refrigeration during its useful shelf life of several months.
It is an object of this invention to provide a method of securing and maintaining an atmosphere of sterile inert gas within an aseptic packaging machine, said gas acting to seal the interior of the packaging machine from entry of microorganisms from the exterior.
It is a further object of this invention to provide a method of insuring that the head space of finished packages be filled with sterile inert gas at essentially atmospheric pressure.
It is a further object to provide a method for using sterile inert gas from the interior of the machine to dry the sealing flange areas of the containers or cups, and to remove liquid sterilant from the cover elements as said elements emerge from a sterilizing bath.
It is yet a further object to provide a method of using sterile inert gas from the interior of the machine to provide a back-up microbiological barrier for the filler section of the packaging machine, and to maintain a slight positive pressure in the interior of the machine.
Other objects will become evident from the description of the invention which follows.